Can you not remove certain items from the dock?

You can.

Note that you will be unable to remove an application from the dock if it is open. Click on the Apple logo -> Force Quit if you are not sure if an application is open.

Either drag the icons from the dock to the trash, or control-click the icon and uncheck 'Keep in Dock'.

Hello Mariah206,

This is a useful document from which to learn all about the dock.

Mac Basics: The Dock